How can I match data only by months and dates and not by year: 1. Data 2. Desired output Answer Convert Time column to datetimes and then to custom format MM/DD/ and then aggregate: If need aggregate sum, mean if duplicates use:
Tag: concatenation
pandas concat dictionary problem with too many indices
I am trying to concat a bunch of data frames which I placed into a dictionary. The following is my code: I get the following error: Shape of passed values is (1924, 55), indices imply (1904, 55) is there a way to avoid this? Answer Based on the comments, what you want is to join (merge) the dataframes not con…
How to concatenate dataframes without overwriting column values
I am trying to create a list of DataFrames in a for loop, and then concatenate them outside of the for loop and write to excel. I have gotten the code to be close, but for some reason the column created inside the for loop ends up being the final value rather each individual value as it loops through. I
Concatenating string to list iteratively
So I’m trying to concatenate a string to a list, but for some reason it only works for the very last values: Input: Output: What i need is: Answer For me this looks like task for map, I would do Output: Explanation: for every pair of corresponding elements from labels and sents I pack first one into lis…
What is point of using the concatenation(+) in Python when commas(,) do the job?
Concatenating throws error, but using a comma instead does the job. Answer As you already been told, your code raises an error because you can only concatenate two strings. In your case one of the arguments of the concatenation is an integer. But your question is more something “plus vs. comma”. W…
Python concat through a list of strings inside a dataframe
I have this df: I need to transform each value in attach list to a link: For example: Where each value is the key in link to download. I tried to use apply func but doesn’t worked: the following error is displayed: TypeError: can only concatenate str (not “list”) to str Answer Take a look at…
How to merge a list composed of many variables and a DataFrame in a single Python Dataframe?
I’ve created a list named “list_data” which contains variables from many files. I also have a dataframe named “observation_data”. I’m trying to merge these 2 files with the key “time”, but nothing to do, all my tentatives fail. Here is my code and my results And…
pandas concat generates nan values
I am curious why a simple concatenation of two dataframes in pandas: of the same shape and both without NaN values can result in a lot of NaN values if joined. How can I fix this problem and prevent NaN values being introduced? Trying to reproduce it like failed e.g. worked just fine as no NaN values were int…
How do I concatenate text files in Python?
I have a list of 20 file names, like [‘file1.txt’, ‘file2.txt’, …]. I want to write a Python script to concatenate these files into a new file. I could open each file by f = open(…), read line by line by calling f.readline(), and write each line into that new file. It doesn…
Concatenating two one-dimensional NumPy arrays
How do I concatenate two one-dimensional arrays in NumPy? I tried numpy.concatenate: But I get an error: TypeError: only length-1 arrays can be converted to Python scalars Answer Use: The arrays you want to concatenate need to be passed in as a sequence, not as separate arguments. From the NumPy documentation…